css实现tab切换时下划线动画效果

效果图

tab切换下划线效果

<template>
	<view class="tab-box">
		<view class="tab-item" @click="testTabClick(index)" :class="tabIndex == index?'active':''" v-for="(item,index) in tabList" :key="index">
			{{item.name}}
		</view>
	</view>
</template>
<script>
	export default{
		data() {
			return {
				tabIndex:0,
				tabList:[{
					name:"电器"
				},{
					name:"衣服"
				},{
					name:"百货"
				},{
					name:"电脑"
				}]
			}
		},
		methods: {
			testTabClick(index) {
				console.log(index)
				this.tabIndex = index
			}
		}
	}
</script>
<style lang="scss" scoped>
	.tab-box{
		display: flex;
		.tab-item{
			flex-shrink: 0;
			padding: 24rpx;
			position: relative;
			transition: all 0.2s linear;
			&::after{
				transition: all 0.2s linear;
				transform: translateX(-50%) scaleX(0);
				content: '';
				width: 50%;
				position: absolute;
				left: 50%;
				bottom: 20rpx;
				border-bottom: 6rpx solid red;
				border-radius: 4rpx;
			}
			&.active{
				&::after{
					content: '';
					width: 50%;
					position: absolute;
					left: 50%;
					transform: translateX(-50%) scaleX(1);
					bottom: 20rpx;
					border-bottom: 6rpx solid red;
				}
			}
		}
	}
</style>